The Leica APO-Summicron-M 50mm f/2 ASPH uses specially developed glass in an apochromatic design which Leica claims minimizes chromatic aberrations. In fact, according to Leica at the time of its announcement, the APO-Summicron-M 50mm f/2 ASPH achieves the best results of any M-series lens in the entire 60-year history of the system. A floating element changes its position relative to the front group during focusing, ensuring that the lens achieves outstanding imaging quality throughout its focusing range, even at close focusing distances.